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Functional analysis of the simian immunodeficiency virus Vpx protein: identification of packaging determinants and a novel nuclear targeting domain.

Publication ,  Journal Article
Mahalingam, S; Van Tine, B; Santiago, ML; Gao, F; Shaw, GM; Hahn, BH
Published in: J Virol
January 2001

The vpx gene products of human immunodeficiency virus type 2 (HIV-2) and of the closely related simian immunodeficiency viruses from sooty mangabeys (SIVsm) and macaques (SIVmac) comprise a 112-amino-acid virion-associated protein that is critical for efficient virus replication in nondividing cells such as macrophages. When expressed in the absence of other viral proteins, Vpx localizes to the nuclear membrane as well as to the nucleus; however, in the context of virus replication Vpx is packaged into virions via interaction with the p6 domain of the Gag precursor polyprotein (p55(gag)). To identify the domains essential for virion incorporation and nuclear localization, site-directed mutations were introduced into the vpx gene of SIVsmPBj1.9 and functionally analyzed. Our results show that (i) mutation of two highly conserved L74 and I75 residues impaired both virion incorporation and nuclear localization of Vpx; (ii) substitution of conserved H82, G86, C87, P103, and P106 residues impaired Vpx nuclear localization but not virion incorporation; (iii) mutations of conserved Y66, Y69, and Y71 residues impaired virion incorporation but not the translocation of Vpx to the nucleus; and (iv) a mutation at E30 (predicted to disrupt an N-terminal alpha-helix) had no effect on either virion incorporation or nuclear localization of Vpx. Importantly, mutations in Vpx which impaired nuclear localization also reduced virus replication in macaque macrophages, suggesting an important role of the carboxyl terminus of Vpx in nuclear translocation of the viral preintegration complex. Analyzing this domain in greater detail, we identified a 26-amino-acid (aa 60 to 85) fragment that was sufficient to mediate the transport of a heterologous protein (green fluorescent protein [GFP]) to the nucleus. Taken together, these results indicate that virion incorporation and nuclear localization are encoded by two partially overlapping domains in the C-terminus of Vpx (aa 60 to 112). The identification of a novel 26-amino-acid nuclear targeting domain provides a new tool to investigate the nuclear import of the HIV-2/SIV preintegration complex.

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Published In

J Virol

DOI

ISSN

0022-538X

Publication Date

January 2001

Volume

75

Issue

1

Start / End Page

362 / 374

Location

United States

Related Subject Headings

  • Virus Replication
  • Virus Assembly
  • Virology
  • Viral Regulatory and Accessory Proteins
  • Structure-Activity Relationship
  • Simian immunodeficiency virus
  • Simian Immunodeficiency Virus
  • Retroviridae Proteins
  • Molecular Sequence Data
  • Macrophages
 

Citation

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Mahalingam, S., Van Tine, B., Santiago, M. L., Gao, F., Shaw, G. M., & Hahn, B. H. (2001). Functional analysis of the simian immunodeficiency virus Vpx protein: identification of packaging determinants and a novel nuclear targeting domain. J Virol, 75(1), 362–374. https://doi.org/10.1128/JVI.75.1.362-374.2001
Mahalingam, S., B. Van Tine, M. L. Santiago, F. Gao, G. M. Shaw, and B. H. Hahn. “Functional analysis of the simian immunodeficiency virus Vpx protein: identification of packaging determinants and a novel nuclear targeting domain.J Virol 75, no. 1 (January 2001): 362–74. https://doi.org/10.1128/JVI.75.1.362-374.2001.
Mahalingam, S., et al. “Functional analysis of the simian immunodeficiency virus Vpx protein: identification of packaging determinants and a novel nuclear targeting domain.J Virol, vol. 75, no. 1, Jan. 2001, pp. 362–74. Pubmed, doi:10.1128/JVI.75.1.362-374.2001.
Mahalingam S, Van Tine B, Santiago ML, Gao F, Shaw GM, Hahn BH. Functional analysis of the simian immunodeficiency virus Vpx protein: identification of packaging determinants and a novel nuclear targeting domain. J Virol. 2001 Jan;75(1):362–374.

Published In

J Virol

DOI

ISSN

0022-538X

Publication Date

January 2001

Volume

75

Issue

1

Start / End Page

362 / 374

Location

United States

Related Subject Headings

  • Virus Replication
  • Virus Assembly
  • Virology
  • Viral Regulatory and Accessory Proteins
  • Structure-Activity Relationship
  • Simian immunodeficiency virus
  • Simian Immunodeficiency Virus
  • Retroviridae Proteins
  • Molecular Sequence Data
  • Macrophages